Despite an intense focus on the safety and quality of the care provided in hospitals in the United States generated by reports from the Institute of Medicine, progress is frustratingly slow. One weakness in our hospital systems is the lack of a clear-cut, reliable assessment of a patient's risk that can be used to communicate among healthcare professionals. Current nursing staffing and physician-coverage practices have accentuated the need for a tool that can highlight changes in a patient's risk not easily apparent to a caregiver unfamiliar with that patient.
Catastrophic deterioration of patients in a hospital is frequently preceded by documented deterioration of physiological parameters. Many systems quantify patient risk for a particular disease or condition. Currently, there is an emphasis on a group of models that quantify risk across diseases, but with a limited goal: to identify patients at extreme risk for cardiac or respiratory arrest. These systems are used to trigger medical emergency teams (MET), rapid response teams (RRT), or critical care outreach (CCO). Currently, most RRT in the United States are triggered by one parameter at a time, and that parameter often represents a significant change in a particular vital sign. For example, a significant change in blood pressure might trigger a call to the RRT, or a significant change in skin color might trigger a call. In some cases, a general feeling that something is not right might lead to a call. Failure of clinical staff to respond to deterioration of respiratory or cerebral function and increase levels of medical intervention will put patients at risk of cardio-respiratory arrest. Inappropriate action in response to observed abnormal physiological and biochemical variables might lead to avoidable death. Suboptimal care prior to admission to a critical care unit can lead to increased mortality.
Because of resource limitations, the number of patients that can be monitored and treated in intensive care units (ICUs) and high dependency units (HDUs) is restricted. The selection of patients who might benefit from critical care is therefore crucial. Identifying medical in-patients at risk of deterioration at an early stage by means of simple protocols based on physiological parameters may reduce the number of pre-ICU resuscitations
One thing that a few hospitals have done is to employ an Early Warning System (EWS) as a means for deciding whether a patient needs to be transferred to the ICU. Other hospitals have developed a Modified Early Warning System (MEWS). Both existing systems typically use a small number of factors such a pulse, blood pressure, temperature, and respiratory rate. For each factor, a partial score is given, and all of these are then tabulated into a total score, which in turn is expressed as a binary recommendation: whether or not to move the patient into the ICU; no other action is suggested, no other information is obtained.
Such systems determine a patient's need to be transferred to the ICU by providing an emergency alert. However, these systems do not provide assistance to the doctor or nurse in helping to anticipate and thereby avoid medical crises, nor are they helpful to the clinical researcher in evaluating the efficacy of procedures and treatments. They convey no health trend information. Also, they are limited in the number of factors analyzed and thus are not very sensitive to general health conditions.